The hypothesis to be tested is that restricted availability of metabolic/nutritional substrates in utero in animals with IUGR at birth induces insulin and IGF resistance during both pre- and postnatal periods. It is proposed that such an effect contributes to retarded growth in utero and persistence of the metabolic derangements postnatally. The investigator plans to use the maternal dietary restriction IUGR rat model to study the changes in the insulin/IGF signaling which occur in these animals in pre- and postnatal periods in order to understand the underlying mechanism.